Neonatology — MCQs

Neonatology Indian Medical PG Practice Questions and MCQs

Question 901: Which of the following statements is true regarding anemia of prematurity?

A. Low reticulocyte response (Correct Answer)
B. Hemoglobin level <10 gm/dL
C. 10 ml/kg packed cell transfusion
D. Microcytic hypochromic type

Explanation: ***Low reticulocyte response*** - Anemia of prematurity results from several factors, including a **blunted erythropoietin response** to anemia, **shortened red blood cell lifespan**, and **rapid growth with increased blood volume requirements**. - The combination of these factors leads to **insufficient red blood cell production** by the bone marrow, reflected by a **low reticulocyte count** despite anemia. - This low reticulocyte response is a **key diagnostic feature** distinguishing it from hemolytic anemias. *Hemoglobin level <10 gm/dL* - While premature infants with anemia of prematurity develop low hemoglobin, a specific cutoff of **<10 gm/dL is not universally definitive** for diagnosis. - Hemoglobin nadirs vary based on **gestational age** (more premature = lower nadir) and occur at different postnatal ages. - Transfusion thresholds are determined by **clinical stability and symptoms**, not just a single Hb value. *10 ml/kg packed cell transfusion* - This describes a **treatment intervention**, not a characteristic of the disease itself. - Transfusion volume is typically **10-15 ml/kg** when indicated, but the decision to transfuse depends on gestational age, postnatal age, clinical stability, and symptoms like apnea or bradycardia. - This is **not a defining feature** of anemia of prematurity. *Microcytic hypochromic type* - Anemia of prematurity is typically **normocytic, normochromic**, not microcytic hypochromic. - **Microcytic hypochromic** anemia suggests **iron deficiency**, which is a different condition. - The red cells in anemia of prematurity have **normal size (MCV) and normal hemoglobin content** per cell.

Question 902: What is the PRIMARY pathophysiological mechanism underlying the most common cause of neonatal hyperbilirubinemia?

A. Inefficient erythropoiesis
B. Immature liver enzyme (Correct Answer)
C. RBC hemolysis
D. Decreased bilirubin excretion

Explanation: ***Immature liver enzyme*** - The most common cause of neonatal hyperbilirubinemia is **physiological jaundice**, and its PRIMARY pathophysiological mechanism is **immature hepatic conjugation** due to deficiency of **UDP-glucuronosyltransferase (UGT1A1)**. - While neonates do produce more bilirubin from RBC breakdown, the **rate-limiting step** is the liver's inability to conjugate unconjugated bilirubin efficiently for excretion. - This immaturity causes accumulation of unconjugated bilirubin, which peaks at **3-5 days of life** and resolves as the enzyme system matures by **7-10 days**. - Key clinical feature: **Unconjugated (indirect) hyperbilirubinemia** in an otherwise healthy term neonate. *RBC hemolysis* - Neonates do have a **shorter RBC lifespan** (70-90 days vs. 120 days in adults) and higher hematocrit, leading to increased bilirubin production (~2-3 times adult rate). - However, this is a **contributory factor**, not the primary mechanism—a normal liver can handle this load easily. - **Pathological hemolysis** (ABO/Rh incompatibility, G6PD deficiency, spherocytosis) causes jaundice through a different mechanism with earlier onset (<24 hours) and more severe hyperbilirubinemia. *Inefficient erythropoiesis* - Ineffective erythropoiesis (abnormal RBC production with intramedullary destruction) is seen in conditions like **thalassemia** and **megaloblastic anemia**. - This can contribute to increased bilirubin load but is not the mechanism in physiological jaundice. - In neonates, erythropoiesis is typically transitioning from fetal to adult hemoglobin but is not pathologically inefficient. *Decreased bilirubin excretion* - Decreased excretion of **conjugated bilirubin** occurs in **cholestatic conditions** (biliary atresia, neonatal hepatitis, choledochal cyst). - This results in **direct (conjugated) hyperbilirubinemia**, not the indirect hyperbilirubinemia seen in physiological jaundice. - While neonates do have relatively decreased enterohepatic circulation clearance, the primary bottleneck is conjugation, not excretion.

Question 903: What is the most common cause of conjugated hyperbilirubinemia in infants?

A. Rotor syndrome
B. Crigler Najjar syndrome
C. Dubin-Johnson syndrome
D. Biliary atresia (Correct Answer)

Explanation: ***Rotor syndrome*** - Characterized by **conjugated hyperbilirubinemia** due to a defect in hepatic uptake and storage of bilirubin [1]. - This condition can lead to elevated levels of **direct (conjugated) bilirubin** without significant liver damage. *Crigler Najjar* - This condition primarily causes **unconjugated hyperbilirubinemia** due to a deficiency of the enzyme **uridine diphosphate glucuronyl transferase** [1]. - It typically presents with **kernicterus** in newborns rather than conjugated bilirubin elevation. *Breast milk jaundice* - Mainly leads to **unconjugated hyperbilirubinemia** due to substances in breast milk that inhibit bilirubin conjugation. - Generally occurs in **breastfed infants** after the first week of life, not presenting with increased conjugated bilirubin. *Gilbert syndrome* - This syndrome is associated with **unconjugated hyperbilirubinemia** due to a genetic defect in bilirubin conjugation [1]. - Typically benign, it does not cause **increased conjugated bilirubin** levels as seen in Rotor syndrome. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, p. 860.

Question 904: A 24-day-old neonate presents with projectile vomiting and failure to gain weight. What is the most likely diagnosis?

A. NEC
B. Duodenal atresia
C. Hirschsprung's disease
D. Congenital Hypertrophic Pyloric Stenosis (Correct Answer)

Explanation: ***Congenital Hypertrophic Pyloric Stenosis*** - The classic presentation includes **projectile, non-bilious vomiting** in a neonate around 2-8 weeks old, leading to **failure to thrive**. - An **olive-shaped mass** (hypertrophied pylorus) may be palpable in the epigastrium. *NEC* - **Necrotizing enterocolitis (NEC)** is an inflammatory disease of the intestine, primarily affecting premature infants. - Symptoms typically include **abdominal distension**, bloody stools, and lethargy, rather than projectile vomiting. *Duodenal atresia* - Presents with **bilious vomiting** within the first 24-48 hours of life due to an obstruction below the ampulla of Vater. - An X-ray would show a **"double bubble" sign**, which is not implied by the provided symptoms. *Hirschsprung's disease* - Characterized by **failure to pass meconium** within the first 24-48 hours and chronic constipation. - Vomiting, if present, is usually **bilious** and associated with abdominal distension, not projectile in nature.

Question 905: Which of the following is a common symptom of neonatal lupus?

A. All of the options
B. Cutaneous lesion (Correct Answer)
C. Thrombocytopenia
D. Heart block

Explanation: ***Cutaneous lesion*** - **Cutaneous lesions** are the most common manifestation of neonatal lupus, typically appearing as an **annular erythematous rash** on the face and scalp. - These lesions often develop after exposure to **ultraviolet light** and usually resolve within 6 months as maternal autoantibodies clear from the infant's system. *Thrombocytopenia* - While **hematologic abnormalities** such as thrombocytopenia can occur in neonatal lupus, they are less common than cutaneous lesions. - **Thrombocytopenia** refers to a low platelet count, which can increase the risk of bleeding. *All of the options* - While all listed options (cutaneous lesions, thrombocytopenia, and heart block) can be features of neonatal lupus, **cutaneous lesions** are the most frequently observed symptom. - Choosing "All of the options" would imply equal commonality or presence of all in every case, which is not accurate. *Heart block* - **Congenital heart block** is a serious, but less common and often irreversible, manifestation of neonatal lupus, caused by maternal antibodies attacking the fetal cardiac conduction system. - It usually presents as **bradycardia** and may require a pacemaker, but it is not the most common symptom overall.

Question 906: A 30-week preterm neonate is admitted to NICU immediately after birth. Which of the following complications is MOST directly related to surfactant deficiency?

A. Increased risk of intraventricular hemorrhage
B. Increased risk of respiratory distress syndrome (Correct Answer)
C. Increased risk of hypothermia
D. Increased risk of hypoglycemia

Explanation: ***Increased risk of respiratory distress syndrome*** - RDS is **most directly caused by surfactant deficiency** in preterm infants, as surfactant production begins around 24-28 weeks and becomes adequate only by 34-36 weeks of gestation. - Surfactant reduces **surface tension in alveoli**, preventing alveolar collapse during expiration. Without adequate surfactant, there is diffuse atelectasis and impaired gas exchange. - Clinical features include **tachypnea, grunting, intercostal retractions, and cyanosis** typically appearing within the first few hours of life. - Chest X-ray shows characteristic **ground-glass appearance with air bronchograms**. *Increased risk of hypothermia* - While preterm infants are indeed at risk for hypothermia due to **large surface area-to-body mass ratio, reduced brown fat, and immature thermoregulation**, this is not directly related to surfactant deficiency. - Hypothermia is primarily related to **thermal regulation mechanisms** rather than lung maturity. *Increased risk of hypoglycemia* - Preterm babies have **limited glycogen stores and immature gluconeogenesis**, increasing hypoglycemia risk. - However, this is related to **metabolic and hepatic immaturity**, not surfactant deficiency. *Increased risk of intraventricular hemorrhage* - Preterm infants are at risk for IVH due to **fragile germinal matrix capillaries and fluctuating cerebral blood flow**. - This is a **neurovascular complication**, not directly related to surfactant deficiency, though severe RDS with hypoxia can be a contributing factor.

Question 907: The recommended ambient temperature for NICU is

A. 20-22° C
B. 22-26° C (Correct Answer)
C. 26-30° C
D. 30-35° C

Explanation: ***22-26° C*** - Maintaining an ambient temperature of **22-26°C** in the NICU is crucial for preventing **cold stress** in neonates. - This temperature range helps to maintain the baby's **core body temperature**, reducing metabolic demands and ensuring optimal thermal regulation. *20-22° C* - While this might be a comfortable room temperature for adults, it is generally **too cold** for newborns in the NICU. - Temperatures below the recommended range can lead to significant **cold stress**, increasing oxygen consumption and metabolic rate in vulnerable infants. *26-30° C* - This temperature range is generally **too warm** for a NICU environment. - Excessive warmth can lead to **hyperthermia** and sweating, which increases fluid loss and can be detrimental to a neonate's health. *30-35°C* - This temperature is **dangerously high** for neonates in the NICU. - Such high temperatures would significantly increase the risk of **hyperthermia, dehydration**, and other severe complications, compromising the infant's well-being.

Question 908: What is the recommended rate for blood transfusion in neonates?

A. 1-5 ml/min (Correct Answer)
B. 10-15 ml/min
C. 15-20 ml/min
D. 5-10 ml/min

Explanation: ***1-5 ml/min*** - The recommended rate for blood transfusion in neonates is **1-5 ml/min** to prevent **circulatory overload** and other complications. - Slower rates are crucial for neonates due to their limited cardiovascular reserves and smaller blood volume. *5-10 ml/min* - This rate is generally **too fast** for routine neonatal blood transfusions, increasing the risk of **fluid overload** and **cardiac strain**. - Rapid administration can lead to complications such as **necrotizing enterocolitis (NEC)** or **respiratory distress**. *10-15 ml/min* - Administering blood at this rate in neonates is **contraindicated** due to the high risk of **cardiovascular compromise**. - It could quickly overwhelm the neonate's circulatory system, leading to severe adverse events. *15-20 ml/min* - This rate is significantly **too rapid** for any neonatal blood transfusion and would almost certainly result in **severe volume overload** and potential cardiac arrest. - Such high rates are only rarely considered in extreme emergency situations, like massive hemorrhage with specific considerations and monitoring.

Question 909: Maximum concentration of dextrose that can be given through peripheral vascular line in neonate?

A. 5%
B. 10%
C. 12.5% (Correct Answer)
D. 25%

Explanation: ***12.5%*** - A maximum dextrose concentration of **12.5%** can typically be administered safely via a **peripheral intravenous line** in neonates. - Higher concentrations risk causing **osmotic damage** to the peripheral vein, leading to **phlebitis** and **thrombosis**. *5%* - While safe, a **5% dextrose** solution may not provide adequate caloric support for many neonates, especially those requiring significant nutritional intake. - It is used for basic hydration and to prevent hypoglycemia but often needs supplementation or higher concentrations for sustained feeding. *10%* - A **10% dextrose** solution is commonly used in neonates via peripheral lines, but concentrations up to 12.5% are generally considered the safe upper limit for extended use. - Exceeding 10% can increase the risk of phlebitis, although it is less severe than with 25%. *25%* - A **25% dextrose** concentration is highly hypertonic and should **never be administered through a peripheral line** in neonates due to the high risk of severe **phlebitis**, **vein damage**, and even **tissue necrosis** if extravasation occurs. - Such high concentrations require a **central venous catheter**.

Question 910: Prophylactic dose of vitamin K given to new born infants at delivery is?

A. 1mg (Correct Answer)
B. 5mg
C. 10mg
D. 15mg

Explanation: ***1mg*** - The standard prophylactic dose of **intramuscular (IM) vitamin K** given to newborns at delivery is **1mg**. - This dose is effective in preventing **Vitamin K Deficiency Bleeding (VKDB)**, also known as hemorrhagic disease of the newborn. *5mg* - A 5mg dose of vitamin K is typically reserved for older children or adults with confirmed **vitamin K deficiency** or certain bleeding disorders. - This dose is generally not given prophylactically to healthy newborns due to the risk of potential adverse effects and it being excessive for prophylaxis. *10mg* - A 10mg dose of vitamin K is significantly higher than the recommended prophylactic dose for newborns and is not routinely administered. - Such a high dose could potentially lead to **hemolysis** or other adverse reactions in neonates. *15mg* - A 15mg dose of vitamin K is far beyond the appropriate prophylactic dose for newborns and is not used in this context. - Administering such a large dose would pose significant risks and is unnecessary for preventing **VKDB**.

Practice by Chapter

Neonatal Resuscitation

Practice Questions

Care of the Normal Newborn

Practice Questions

Prematurity and Low Birth Weight

Practice Questions

Respiratory Distress Syndrome

Practice Questions

Neonatal Jaundice

Practice Questions

Neonatal Sepsis

Practice Questions

Necrotizing Enterocolitis

Practice Questions

Intraventricular Hemorrhage

Practice Questions

Persistent Pulmonary Hypertension

Practice Questions

Perinatal Asphyxia

Practice Questions

Neonatal Seizures

Practice Questions

Congenital Anomalies

Practice Questions

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